In this riveting middle grade thriller set on The Boundless—a seven-mile-long train crossing in late 19th century Canada— Oppel (Airborn, Eos, 2004) mixes railway history, creatures from folklore, and a splash of steampunk into an exciting yarn about a boy seeking his own adventure. Will Everett has always felt himself to be in the shadow of his father’s adventures, but when he inadvertently gets on the wrong side of a gang of ruthless thieves who are after a treasure hidden on a train, he has to rely on himself, along with two mysterious new friends from the Zirkus Dante: the ringmaster Mr. Dorian and Maren the Marvelous, a young wirewalker and escape artist. The characters whom Will encounters as the train rattles across plains and through snow-laden mountain passes are fully developed, and the lead ones, even the cold-hearted villain, are especially richly layered and intriguingly complex. The novel, written in the present tense, swings between cinematic action sequences and detailed and enthralling descriptions of the settings. Along the way, it touches lightly, but not superficially, on class distinctions, conflict between Native Americans and settlers, and exploitation of the colonists. Culminating in a thrilling and satisfying resolution that loops back to earlier events, there is a hint that we may see further adventures of Will and Maren in the future. Review based on an ARC.Hayley Beale, San Francisco Univ High School